1. Field of the Invention
This invention relates to a needling apparatus for making a patterned felt web, which apparatus comprises at least one needle board, connected to a needle board drive, a feed drive for feeding the felt web through a felt guide between a felt support and a stripper, and means for adjusting the stroke position of the needle board relative to the felt guide between an idle stroke position and a working stroke position for the largest depth of needle penetration.
2. Description of the Prior Art
In needling apparatuses of that iknd, forked needles are used to form fiber loops, which protrude above the surface of the smooth web of needled felt. Such surface texture may provide a pattern on the felt web. The design of such pattern will obviously depend on the length of the feed movement which is imparted to the felt web as it is needled and on the depth of penetration and on the density of penetration of the needles. The depth of penetration of the needles will be determined by the setting of the relative stroke position of the needle board relative to the felt guide. Either the felt guide is adjusted relative to a predetermined stroke position of the needle board or the stroke position of the needle board is adjusted relative to the stationary felt guide. Because the setting of the stroke position of the needle board relative to the felt guide can be effected in a range between a working stroke position for the largest depth of penetration and an idle stroke position in which there is no penetration, widely varying surface patterns of the felt web including length sections having different loop lengths and length sections having no loops may result. The known needling apparatuses of that kind have the disadvantage that the feeding speed of the felt web must be determined in dependence on that patterned length section in which the largest loops and the densest loops are formed so that said feeding speed cannot be increased beyond a predetermined limit and, as a result, there is a limit to the throughput capacity of the needling apparatus.